Hydropower Planning Based ASTER GDEM And Arc Hydro Terrain Extraction And Hydrological Analysis Practical Method

Engineers can not make correct decisions in water resource and hydropower planning without topographic, hydrologic, meteorological and geological information support. Small and medium size hydropower stations and reservoirs are often built in sparsely inhabited mountainous areas. However, it is often encountered that engineers have to carry out hydropower and water resource planning in such areas that are lack of the basic geographical information mentioned above. So it is critical to correctly and efficiently acquire the geographical information with the aid of 3S technologies for hydropower and water resource planning.Taking into account that at the preliminary stage of hydropower planning the accuracy requirement of topographical information is limited, this study put forward a new approach to extract topographical information from a space borne remote sensing data and to do hydrologic analysis by ArcHydro Tools for hydropower planning. This methods has been applied to a practical hydropower project and it's usefulness and feasibility has been proven. The contents of the paper are summarized as follows:1. The global topographical data—Aster GDEM and its data structure and characteristics have been reviewed. ArcHydro Data model and the functions of ArcHydro Tools have been studied for hydrologic analysis.2. The principles of extracting hydrologic information from DEM by Arc Hydro tool has been reviewed, and the methods to process ASTER GDEM has been given by the authors.3. The technique points of raster DEM based ArcHydro analysis in ArcGIS9.3 environment have been given by the authors, such as terrain processing, hydrologic analysis, watershed area analysis, run-off analysis.4. The topographic and hydrologic characteristics of a planning area as a case study have been extracted by using ASTER GDEM data and 1/50000 topographic map respectively. The run-off of a hydropower station in the area has been analyzed by the topographic and hydrologic characteristics of the planning area. The analysis results has shown that the area and run-off of the watershed of the planning area by the two approaches are very close, and the error is within five percent, which proved that the methodology put forward by the authors are useful and feasible.5. A computer program for hydrologic frequency analysis has been developed by the author, in which optimized parameters, such as Cv and Cs, of Pearson TypeⅢcure can be given to determine design value of a hydrologic characteristics under a given probability, such as run-off or precipitation.